Fix potential compiler warnings in public headers [-Wshadow]

These warnings would be issued if users compiled their programs with
diagnostics '-Wshadow' turned on using gcc, clang, and maybe other
compilers.

FL/Fl_GIF_Image.H

@@ -1,7 +1,7 @@
 //
 // GIF image header file for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2023 by Bill Spitzak and others.
+// Copyright 1998-2024 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -69,7 +69,7 @@ protected:
     GIF_FRAME(int frame, uchar *data) : ifrm(frame), bptr(data) {}
     GIF_FRAME(int frame, int W, int H, int fx, int fy, int fw, int fh, uchar *data) :
       ifrm(frame), width(W), height(H), x(fx), y(fy), w(fw), h(fh), bptr(data) {}
-    void disposal(int mode, int delay) { dispose = mode; this->delay = delay; }
+    void disposal(int mode, int time) { dispose = mode; this->delay = time; }
     void colors(int nclrs, int bg, int tp) { clrs = nclrs; bkgd = bg; trans = tp; }
   };
 

FL/Fl_Paged_Device.H

@@ -1,7 +1,7 @@
 //
 // Printing support for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2016 by Bill Spitzak and others.
+// Copyright 2010-2024 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -116,12 +116,11 @@ public:
   /** Synonym of draw(Fl_Widget*, int, int) */
   void print_widget(Fl_Widget* widget, int delta_x = 0, int delta_y = 0) {draw(widget, delta_x, delta_y);}
   /** Synonym of draw_decorated_window(Fl_Window*, int, int) */
-  void print_window(Fl_Window *win, int x_offset = 0, int y_offset = 0) {
+  void print_window(Fl_Window *win, int x_off = 0, int y_off = 0) {
-    draw_decorated_window(win, x_offset, y_offset);
+    draw_decorated_window(win, x_off, y_off);
   }
   virtual int end_page (void);
   virtual void end_job (void);
 };
 
 #endif // Fl_Paged_Device_H
-